CARSON CITY, Nev. - The number of frozen water pipes increased during the recent cold snap and more may come to light as temperatures warm, according to Curtis Horton of Carson City's Public Works Department.Horton, departmental operations chief, said Tuesday that calls about frozen pipes at homes and mobile homes had come in at a higher-than-normal rate, above the typical 20 to 30 calls a week during cold weather. He urged mobile home owners to check their skirting and other homeowners to check crawl spaces and boxes that cover water connections outside their houses.A sprinkler water pipe rupture Tuesday evening forced the evacuation of three patients from the long term acute care facility located at Carson Tahoe Specialty Medical Center.According to a press release from Carson Tahoe Health, the patients were moved to Carson Tahoe Regional Medical Center. By 7:15, the flood had been contained.Horton also said the city had a frozen water meter early Tuesday that was repaired. "That happens every now and then," he said, adding that the meter actually may have broken earlier but wasn't noticed until the morning hours. But other than that case, on Plantation Drive between Ash Canyon Road and Manhattan Drive on the west side of Carson City, he said city government wasn't experiencing any problems.He expects problems to continue as long as the cold does, and in warmer weather some additional problems will be caught by homeowners as pipes start to unfreeze."It's a sustained cold. This has been cold for the past couple of weeks," he said, adding, "It has been keeping us busy."The bitter cold that has gripped the region for nearly a week was subsiding Tuesday as a warmer front moved in. By afternoon, the record-setting cold that caused pipes to burst as far south as Las Vegas was making its way east. The record low of minus 24 along the Utah line in Ely on Monday had warmed to minus 8 early Tuesday and the single digits in Reno were forecast to approach 40 degrees on Wednesday.The extreme wintry conditions also led Gov. Brian Sandoval to declare a state of emergency Tuesday in an effort to allow more propane deliveries in Nevada. It suspends federal regulations that limit the number of hours driven by a commercial operator in a shift. The declaration applies to commercial truck drivers bringing in propane.Sandoval's declaration, which he called a "precautionary measure," came a day after a record low of minus 24 degrees was set along the Utah line in Ely. Las Vegas's high temperature on Monday also set a record low for that date.In Stateline, fire officials restored fire protection systems at four Lake Tahoe casinos after sub-zero temperatures caused pipes to freeze and break at each of the high rises on Tahoe's south shore.The casinos on the California-Nevada border were cleaning up Tuesday after fire crews had to spend the night on site until the sprinklers and other emergency systems were verified to be operating safely. A record low of minus 11 degrees started the trouble Monday morning."It was a little crazy for us for a while, but it was pretty quiet overnight," Tahoe Douglas fire marshal Eric Guevin told The Associated Press on Tuesday. "We've been able to get some heat in some of those questionable areas and all the fire protection systems are in place now."Guevin said a damage estimate wasn't immediately available but he said the worst appeared to be at Harrah's where broken pipes sent thousands of gallons into the main 18-story tower and a high-roller gambling area. He wasn't aware of any gamblers or gaming tables that were harmed but he said some slot machines in the high-roller area at Harrah's apparently were damaged and patrons had to be evacuated from that area.Two sprinkler heads also broke at Harvey's casino, and another broken pipe sent water into the loading dock at the Horizon casino. At the MontBleu, an antifreeze system meant to prevent pipe breakage froze, he said.Now, Guevin fears trouble is brewing in frozen pipes at homes that may be sitting vacant around Lake Tahoe, where the temperature was forecast to warm slightly by Tuesday afternoon."These pipes at the casinos are in well-heated, well-maintained buildings, so the bigger concern for us are homeowners whose pipes are probably freezing solid in vacation homes," Guevin said."As soon as it warms up, those are going to let go and we are going to be busy," he said. So far, they'd only had a handful of such incidents, he added.City officials in Reno who scrambled to find housing for hundreds of homeless in single-digit conditions the past few days welcomed significantly warmer weather Tuesday. In neighboring Sparks, the city council declared a limited state of emergency on Monday, mostly as a formality to free up money to repair a pair of 7-foot diameter sewer lines that broke in the cold late last week.